Substituted 8-[6-amino-3-pyridyl]xanthines

ABSTRACT

The present invention provides substituted 8-[6-amino-3-pyridyl]xanthines like the compound shown in the following formula: 
                         
and pharmaceutical compositions that are selective antagonists of A 2B  adenosine receptors (ARs). These compounds and compositions are useful as pharmaceutical agents.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the priority benefits of U.S. ProvisionalApplication No. 60/805,030, filed 16 Jun. 2006, and U.S. ProvisionalApplication No. 60/805,564, filed 22 Jun. 2006, which are expresslyincorporated fully herein by reference.

FIELD OF THE INVENTION

The present invention relates to substituted8-[6-amino-3-pyridyl]xanthines and pharmaceutical compositions that areselective antagonists of A_(2B) adenosine receptors (ARs). Thesecompounds and compositions are useful as pharmaceutical agents.

BACKGROUND OF THE INVENTION

The alkylxanthine theophylline (below), a weak non-selective adenosine

antagonist (See Linden, J., et al., Cardiovascular Biology of Purines,eds. G. Burnstock, et al., 1998, pp 1-20), is useful therapeutically forthe treatment of asthma. However, its use is associated with unpleasantside effects, such as insomnia and diuresis. In recent years, the use oftheophylline as a bronchodilator, for relief of asthma, has beensupplanted by drugs of other classes, e.g., selective β2-adrenergicagonists, corticosteroids, and recently leukotriene antagonists. Thesecompounds also have limitations. Thus, the development of atheophylline-like drug with reduced side effects is still desirable.

It has been recognized that theophylline and its closely relatedanalogue caffeine block endogenous adenosine acting as a local modulatorof adenosine receptors in the brain and other organs at therapeuticallyuseful doses. Adenosine activates four subtypes of G protein-coupledadenosine receptors (ARs), A₁/A_(2A)/A_(2B)/A₃. Enprofylline (below) isanother example of a xanthine that has been reported to block A_(2B)adenosine receptors and is used

to treat asthma. It has also been shown by LaNoue et al (U.S. Pat. No.6,060,481) that selective adenosine A_(2B) antagonists are useful forimproving insulin sensitivity in a patient.

It has been reported that therapeutic concentrations of theophylline orenprofylline block human A_(2B) receptors, and it has been proposed thatantagonists selective for this subtype may have potential use asantiasthmatic agents. (See Feoktistov, I., et al., Pharmacol. Rev. 1997,49, 381-402; and Robeva, A. S., et al., Drug Dev. Res. 1996, 39,243-252). Enprofylline has a reported K_(i) value of 7 μM and issomewhat selective in binding to human A_(2B) ARs. (See Robeva, A. S.,et al., Drug Dev. Res. 1996, 39, 243-252 and Linden, J., et al., Mol.Pharmacol. 1999, 56, 705-713). A_(2B) ARs are expressed in some mastcells, such as the BR line of canine mastocytoma cells, which appear tobe responsible for triggering acute Ca²⁺ mobilization and degranulation.(See Auchampach, J. A., et al., Mol. Pharmacol. 1997, 52, 846-860 andForsyth, P., et al., Inflamm. Res. 1999, 48, 301-307). A_(2B) ARs alsotrigger Ca²⁺ mobilization, and participate in a delayed IL8 release fromhuman HMC-1 mast cells. Other functions associated with the A_(2B) ARare the control of cell growth and gene expression, (See Neary, J., etal., Trends Neurosci. 1996, 19, 13-18) endothelial-dependentvasodilation (See Martin, P. L., et al., J. Pharmacol. Exp. Ther. 1993,265, 248-253), and fluid secretion from intestinal epithelia. (SeeStrohmeier, G. R., et al., J. Biol. Chem. 1995, 270, 2387-2394).Adenosine acting through A_(2B) ARs has also been reported to stimulatechloride permeability in cells expressing the cystic fibrosis transportregulator. (See Clancy, J. P., et al., Am. J. Physiol. 1999, 276,C361-C369.)

Recently Linden et al (U.S. Pat. No. 6,545,002) have described a newgroup of compounds and pharmaceutical compositions that are selectiveantagonists of A_(2B) adenosine receptors (ARs).

Although adenosine receptor subtype-selective probes are available forthe A₁, A_(2A), and A₃ ARs, only few selective antagonists are known forthe A_(2B) receptor. Therefore, a continuing need exists for compoundsthat are selective A_(2B) receptor antagonists.

SUMMARY OF THE INVENTION

The present invention provides substituted8-[6-amino-3-pyridyl]xanthines or stereoisomers or pharmaceuticallyacceptable salts that act as antagonists of A_(2B) adenosine receptors.

The invention also provides pharmaceutical compositions comprising acompound of the present invention or stereoisomer or a pharmaceuticallyacceptable salt thereof in combination with a pharmaceuticallyacceptable excipient.

Additionally, the invention provides a therapeutic method for treating apathological condition or symptom in a mammal, such as a human, whereinthe activity, e.g., over-activity, of adenosine A_(2B) receptors isimplicated in one or more symptoms of the pathology and antagonism(i.e., blocking) is desired to ameliorate such symptoms. Thus, thepresent invention provides a method of treating a disease comprisingadministering a therapeutically effective amount of at least onecompound of the present invention or a stereoisomer or pharmaceuticallyacceptable salt thereof, wherein the disease is selected from asthma,allergies, allergic diseases (e.g., allergic rhinitis and sinusitis),autoimmune diseases (e.g., lupus), diarrheal diseases, insulinresistance, diabetes (e.g., Type I and Type II), prevention of mast celldegranulation associated with ischemia/reperfusion injuries, heartattack, inhibition of angiogenesis in neoplastic tissues, and inhibitionof angiogenesis in diabetic retinopathy or hyperbaric oxygen-inducedretinopathy.

The invention provides a novel compound of the present invention for usein medical therapy.

The invention also provides the use of a novel compound of the presentinvention for the manufacture of a medicament for the treatment of apathological condition or symptom in a mammal, which is associated withdeleterious A_(2B) receptor activation or activity.

The invention also includes a method comprising contacting a compound ofthe present invention, optionally having a radioactive isotope(radionuclide), such as, for example, tritium, radioactive iodine (e.g.,¹²⁵I for binding assays or ¹²³I for Spectral Imaging) and the like, withtarget A_(2B) adenosine receptor sites comprising said receptors, invivo or in vitro, so as to bind to said receptors. Cell membranescomprising bound A_(2B) adenosine receptor sites can be used to measurethe selectivity of test compounds for adenosine receptor subtypes or canbe used as a tool to identify potential therapeutic agents for thetreatment of diseases or conditions associated with A_(2B)-receptormediation, by contacting said agents with said radioligands andreceptors, and measuring the extent of displacement of the radioligandand/or binding of the agent.

DETAILED DESCRIPTION OF THE INVENTION

Applicants have discovered that the substituted8-[6-amino-3-pyridyl]xanthines shown below can be useful for thetreatment diseases or conditions associated with deleterious A_(2B)receptor activation or activity.

In an aspect of the invention, there is provided a compound selectedfrom:

or a stereoisomer or pharmaceutically acceptable salt thereof.

In another aspect of the invention, there is provided a pharmaceuticalcomposition comprising: (a) a therapeutically effective amount of acompound described above; and (b) a pharmaceutically acceptableexcipient.

In another aspect of the invention, there is provided a therapeuticmethod for preventing or treating a pathological condition or symptom ina mammal, wherein the activity of adenosine A_(2B) receptors isimplicated and antagonism of its action is desired comprisingadministering to the mammal a therapeutically effective amount of acompound of the present invention.

In another aspect of the invention, there is provided a method oftreating a disease comprising administering a therapeutically effectiveamount of at least one compound of the present invention or astereoisomer or pharmaceutically acceptable salt thereof, wherein thedisease is selected from asthma, allergies, allergic diseases (e.g.,allergic rhinitis and sinusitis), autoimmune diseases (e.g., lupus),diarrheal diseases, insulin resistance, diabetes, prevention of mastcell degranulation associated with ischemia/reperfusion injuries, heartattack, inhibition of angiogenesis in neoplastic tissues, and inhibitionof angiogenesis in diabetic retinopathy or hyperbaric oxygen-inducedretinopathy.

In another aspect of the invention, there is provided the compound ofthe present invention for use in medical therapy.

In another aspect, there is provided a use of a compound of theinvention, for the manufacture of a medicament useful for the treatmentof a disease in a mammal.

It is understood that any aspect or feature of the present inventionwhether characterized as preferred or not characterized as preferred maybe combined with any other aspect or feature of the invention, whethersuch other feature is characterized as preferred or not characterized aspreferred.

As is recognized by one of ordinary skill in the art, the imidazole ringof the compounds of the present invention may exist in tautomeric formsor as tautomers, and thus are also included within the scope of theinvention. The tautomeric isomers are represented as the structures (Ia)and (Ib):

wherein R, R¹, R², X, and Z are as defined herein.

By naming or referring to one compound, for example, it is understoodfor the purposes of the present application that its correspondingtautomer is also intended.

The terms “include”, “for example”, “such as”, and the like are usedillustratively and are not intended to limit the present invention.

The indefinite articles “a” and “an” mean “at least one” or “one ormore” when used in this application, including the claims, unlessspecifically indicated otherwise.

It will be appreciated by those skilled in the art that compounds of theinvention having a chiral center may exist in and be isolated inoptically active, and racemic forms. Some compounds may exhibitpolymorphism. It is to be understood that the present inventionencompasses any racemic, optically-active, polymorphic, orstereoisomeric form, or mixtures thereof, of a compound of theinvention, which possess the useful properties described herein; itbeing well known in the art how to prepare optically active forms (forexample, by resolution of the racemic form by recrystallizationtechniques, by synthesis from optically-active starting materials, bychiral synthesis, or by chromatographic separation using a chiralstationary phase) and how to determine therapeutic activity using thestandard tests described herein or using other similar tests which arewell known in the art.

Mammal and patient covers warm blooded mammals that are typically undermedical care (e.g., humans and domesticated animals). Examples ofmammals include (a) feline, canine, equine, bovine, and human and (b)human.

“Treating” or “treatment” covers the treatment of a disease-state in amammal, and includes: (a) preventing the disease-state from occurring ina mammal, in particular, when such mammal is predisposed to thedisease-state but has not yet been diagnosed as having it; (b)inhibiting the disease-state, e.g., arresting it development; (c)relieving the disease-state, e.g., causing regression of the diseasestate until a desired endpoint is reached; and/or (d) eliminating thedisease-state, e.g., causing cessation of the disease state and/or itseffects. Treating also includes the amelioration of a symptom of adisease (e.g., lessen the pain or discomfort), wherein such ameliorationmay or may not be directly affecting the disease (e.g., cause,transmission, expression, etc.).

“Pharmaceutically acceptable salts” refer to derivatives of thedisclosed compounds wherein the parent compound is modified by makingacid or base salts thereof. Examples of pharmaceutically acceptablesalts include, but are not limited to, mineral or organic acid salts ofbasic residues such as amines; alkali or organic salts of acidicresidues such as carboxylic acids; and the like. The pharmaceuticallyacceptable salts include the conventional non-toxic salts or thequaternary ammonium salts of the parent compound formed, for example,from non-toxic inorganic or organic acids. For example, suchconventional non-toxic salts include, but are not limited to, thosederived from inorganic and organic acids selected from1,2-ethanedisulfonic, 2-acetoxybenzoic, 2-hydroxyethanesulfonic, acetic,ascorbic, benzenesulfonic, benzoic, bicarbonic, carbonic, citric,edetic, ethane disulfonic, ethane sulfonic, fumaric, glucoheptonic,gluconic, glutamic, glycolic, glycollyarsanilic, hexylresorcinic,hydrabamic, hydrobromic, hydrochloric, hydroiodide, hydroxymaleic,hydroxynaphthoic, isethionic, lactic, lactobionic, lauryl sulfonic,maleic, malic, mandelic, methanesulfonic, napsylic, nitric, oxalic,pamoic, pantothenic, phenylacetic, phosphoric, polygalacturonic,propionic, salicyclic, stearic, subacetic, succinic, sulfamic,sulfanilic, sulfuric, tannic, tartaric, and toluenesulfonic.

The pharmaceutically acceptable salts of the present invention can besynthesized from the parent compound that contains a basic or acidicmoiety by conventional chemical methods. Generally, such salts can beprepared by reacting the free acid or base forms of these compounds witha stoichiometric amount of the appropriate base or acid in water or inan organic solvent, or in a mixture of the two; generally, non-aqueousmedia like ether, ethyl acetate, ethanol, isopropanol, or acetonitrileare preferred. Lists of suitable salts are found in Remington'sPharmaceutical Sciences, 18th ed., Mack Publishing Company, Easton, Pa.,1990, p 1445, the disclosure of which is hereby incorporated byreference.

“Therapeutically effective amount” includes an amount of a compound ofthe present invention that is effective when administered alone or incombination to treat an indication listed herein. “Therapeuticallyeffective amount” also includes an amount of the combination ofcompounds claimed that is effective to treat the desired indication. Thecombination of compounds is preferably a synergistic combination.Synergy, as described, for example, by Chou and Talalay, Adv. EnzymeRegul. 1984, 22:27-55, occurs when the effect of the compounds whenadministered in combination is greater than the additive effect of thecompounds when administered alone as a single agent. In general, asynergistic effect is most clearly demonstrated at sub-optimalconcentrations of the compounds. Synergy can be in terms of lowercytotoxicity, increased effect, or some other beneficial effect of thecombination compared with the individual components.

Specific and preferred values listed for radicals, substituents, andranges, are for illustration only; they do not exclude other definedvalues or other values within defined ranges for the radicals andsubstituents.

Synthesis

The compounds of the present invention can be prepared by the methodsdescribed in US 2005/0065341, the contents of which are incorporatedherein by reference.

The compounds of the present invention can also be prepared by themethods described in P. J. Scammells, et al., J. Med. Chem. 37,2704-2712 (1994). A diamino-1,3-disubstituted uracil is acylated with6-chloronicotinoyl chloride in pyridine at 5° C. to provide thecompounds of Formula (5a). The resulting amide (5a) is cyclized byrefluxing in an aqueous sodium hydroxide solution to provide thecompound A. 6-Chloronicotinoyl chloride is prepared by refluxing6-hydroxynicotinic acid in thionyl chloride using DMF as the catalyst asshown in Reaction Scheme 1.

Compound A can be alkylated with alkyl bromide or iodide to providecompounds of Formula A¹. Compounds A or A¹ react with substituted amineat 150-160° C. in a pressure tube to give compounds of Formula B or B¹.Compounds of Formula B¹ where R⁴ is hydrogen can react with acylchloride to afford compounds where R⁴ is —C(O)R⁶(C).

The following abbreviations have been used herein:

-   -   [¹²⁵I]ABA [¹²⁵I]N⁶-(4-aminobenzyl)-adenosine    -   ¹²⁵I-ABOPX        ¹²⁵I-3-(4-amino-3-iodobenzyl)-8-oxyacetate-1-propyl-xanthine    -   AR adenosine receptor    -   CGS 21680        2-[4-[(2-carboxyethyl)phenyl]ethyl-amino]-5N-N-ethylcarbamoyl        adenosine    -   CPX 8-cyclopentyl-1,3-dipropylxanthine    -   DMEM Dulbecco modified eagle medium    -   DMF N,N-dimethylformamide    -   DMSO dimethylsulfoxide    -   EDTA ethylenediaminetetraacetate    -   HEK cells human embryonic kidney cells    -   K_(i) equilibrium inhibition constant    -   NECA 5′-(N-ethylcarbamoyl)adenosine    -   R-PIA R-N⁶-phenylisopropyladenosine    -   TEA triethylamine    -   TLC Thin layer chromatography    -   ZM 241385        4-(2-[7-amino-2-{furyl}{1,2,4}triazolo{2,3-a}{1,3,5}triazin-5-ylaminoethyl)phenol

The compounds of the present invention can be formulated aspharmaceutical compositions and administered to a mammalian host, suchas a human patient in a variety of forms adapted to the chosen route ofadministration, e.g., orally or parenterally, by intravenous,intramuscular, topical, inhalation or subcutaneous routes. Exemplarypharmaceutical compositions are disclosed in “Remington: The Science andPractice of Pharmacy”, A. Gennaro, ed., 20th edition, Lippincott,Williams & Wilkins, Philadelphia, Pa.

Thus, the present compounds may be systemically administered, e.g.,orally, in combination with a pharmaceutically acceptable excipient suchas an inert diluent or an assimilable edible carrier. They may beenclosed in hard or soft shell gelatin capsules, may be compressed intotablets or may be incorporated directly with the food of the patient'sdiet. For oral therapeutic administration, the active compound may becombined with one or more excipients and used in the form of ingestibletablets, buccal tablets, troches, capsules, elixirs, suspensions,syrups, wafers, and the like. Such compositions and preparations shouldcontain at least 0.1% of active compound. The percentage of thecompositions and preparations may, of course, be varied and mayconveniently be between about 2 to about 60% of the weight of a givenunit dosage form. The amount of active compound in such therapeuticallyuseful compositions is such that an effective dosage level will beobtained.

The tablets, troches, pills, capsules, and the like may also contain thefollowing: binders such as gum tragacanth, acacia, corn starch orgelatin; excipients such as dicalcium phosphate; a disintegrating agentsuch as corn starch, potato starch, alginic acid and the like; alubricant such as magnesium stearate; and a sweetening agent such assucrose, fructose, lactose or aspartame or a flavoring agent such aspeppermint, oil of wintergreen or cherry flavoring may be added. Whenthe unit dosage form is a capsule, it may contain, in addition tomaterials of the above type, a liquid carrier, such as a vegetable oilor a polyethylene glycol. Various other materials may be present ascoatings or to otherwise modify the physical form of the solid unitdosage form. For instance, tablets, pills or capsules may be coated withgelatin, wax, shellac or sugar and the like. A syrup or elixir maycontain the active compound, sucrose or fructose as a sweetening agent,methyl and propylparabens as preservatives, a dye and flavoring such ascherry or orange flavor. Of course, any material used in preparing anyunit dosage form should be pharmaceutically acceptable and substantiallynon-toxic in the amounts employed. In addition, the active compound maybe incorporated into sustained-release preparations and devices.

The active compound may also be administered intravenously orintraperitoneally by infusion or injection. Solutions of the activecompound or its salts can be prepared in water, optionally mixed with anontoxic surfactant. Dispersions can also be prepared in glycerol,liquid polyethylene glycols, triacetin, and mixtures thereof and inoils. Under ordinary conditions of storage and use, these preparationscontain a preservative to prevent the growth of microorganisms.

The pharmaceutical dosage forms suitable for injection or infusion caninclude sterile aqueous solutions or dispersions or sterile powderscomprising the active ingredient which are adapted for theextemporaneous preparation of sterile injectable or infusible solutionsor dispersions, optionally encapsulated in liposomes. In all cases, theultimate dosage form should be sterile, fluid and stable under theconditions of manufacture and storage. The liquid carrier or vehicle canbe a solvent or liquid dispersion medium comprising, for example, water,ethanol, a polyol (for example, glycerol, propylene glycol, liquidpolyethylene glycols, and the like), vegetable oils, nontoxic glycerylesters, and suitable mixtures thereof. The proper fluidity can bemaintained, for example, by the formation of liposomes, by themaintenance of the required particle size in the case of dispersions orby the use of surfactants. The prevention of the action ofmicroorganisms can be brought about by various antibacterial andantifungal agents, for example, parabens, chlorobutanol, phenol, sorbicacid, thimerosal, and the like. In many cases, it will be preferable toinclude isotonic agents, for example, sugars, buffers or sodiumchloride. Prolonged absorption of the injectable compositions can bebrought about by the use in the compositions of agents delayingabsorption, for example, aluminum monostearate and gelatin.

Sterile injectable solutions are prepared by incorporating the activecompound in the required amount in the appropriate solvent with variousof the other ingredients enumerated above, as required, followed byfilter sterilization. In the case of sterile powders for the preparationof sterile injectable solutions, the preferred methods of preparationare vacuum drying and the freeze drying techniques, which yield a powderof the active ingredient plus any additional desired ingredient presentin the previously sterile-filtered solutions.

For topical administration, the present compounds may be applied in pureform, i.e., when they are liquids. However, it will generally bedesirable to administer them to the skin as compositions orformulations, in combination with a dermatologically acceptable carrier,which may be a solid or a liquid.

Useful solid carriers include finely divided solids such as talc, clay,microcrystalline cellulose, silica, alumina and the like. Useful liquidcarriers include water, alcohols or glycols or water-alcohol/glycolblends, in which the present compounds can be dissolved or dispersed ateffective levels, optionally with the aid of non-toxic surfactants.Adjuvants such as fragrances and additional antimicrobial agents can beadded to optimize the properties for a given use. The resultant liquidcompositions can be applied from absorbent pads, used to impregnatebandages and other dressings or sprayed onto the affected area usingpump-type or aerosol sprayers.

Thickeners such as synthetic polymers, fatty acids, fatty acid salts andesters, fatty alcohols, modified celluloses or modified mineralmaterials can also be employed with liquid carriers to form spreadablepastes, gels, ointments, soaps, and the like, for application directlyto the skin of the user.

Examples of useful dermatological compositions which can be used todeliver the compounds of the present invention to the skin are known tothe art; for example, see Jacquet et al. (U.S. Pat. No. 4,608,392),Geria (U.S. Pat. No. 4,992,478), Smith et al. (U.S. Pat. No. 4,559,157)and Wortzman (U.S. Pat. No. 4,820,508). Useful dosages of the compoundsof the present invention can be determined by comparing their in vitroactivity, and in vivo activity in animal models. Methods for theextrapolation of effective dosages in mice, and other animals, to humansare known to the art; for example, see U.S. Pat. No. 4,938,949.

Generally, the concentration of the compound(s) of the present inventionin a liquid composition, such as a lotion, will be from (a) about 0.1-25wt % and (b) about 0.5-10 wt %. The concentration in a semi-solid orsolid composition such as a gel or a powder will be (a) about 0.1-5 wt %and (b) about 0.5-2.5 wt %.

The amount of the compound or an active salt or derivative thereof,required for use in treatment will vary not only with the particularcompound or salt selected but also with the route of administration, thenature of the condition being treated, and the age and condition of thepatient and will be ultimately at the discretion of the attendantphysician or clinician. In general, however, a suitable dose will be inthe range of from (a) about 1.0-100 mg/kg of body weight per day, (b)about 10-75 mg/kg of body weight per day, and (c) about 5-20 mg perkilogram body weight per day.

The compound can be conveniently administered in unit dosage form; e.g.,tablets, caplets, etc., containing (a) about 4-400 mg, (b) about 10-200mg, and (c) about 20-100 mg of active ingredient per unit dosage form.

Ideally, the active ingredient should be administered to achieve peakplasma concentrations of the active compound of from (a) about 0.02-20μM, (b) about 0.1-10 μM, and (c) about 0.5-5 μM. These concentrationsmay be achieved, for example, by the intravenous injection of a0.005-0.5% solution of the active ingredient, or orally administered asa bolus containing about 4-400 mg of the active ingredient.

The compounds of the invention can also be administered by inhalationfrom an inhaler, insufflator, atomizer or pressurized pack or othermeans of delivering an aerosol spray. Pressurized packs may comprise asuitable propellant such as carbon dioxide or other suitable gas. Incase of a pressurized aerosol, the dosage unit may be determined byproviding a value to deliver a metered amount. The inhalers,insufflators, atomizers are fully described in pharmaceutical referencebooks such as Remington's Pharmaceutical Sciences Volumes 16 (1980) or18 (1990) Mack Publishing Co.

The desired dose may conveniently be presented in a single dose or asdivided doses administered at appropriate intervals, for example, astwo, three, four or more sub-doses per day. The sub-dose itself may befurther divided, e.g., into a number of discrete loosely spacedadministrations; such as multiple inhalations from an insufflator or byapplication of a plurality of drops into the eye.

All patents, patent applications, books and literature cited in thespecification are hereby incorporated by reference in their entirety. Inthe case of any inconsistencies, the present disclosure, including anydefinitions therein will prevail.

The invention has been described with reference to various specific andpreferred embodiments and techniques. However, it should be understoodthat many variations and modifications may be made while remainingwithin the spirit and scope of the invention.

EXAMPLES Pharmacology

The ability of compounds of the invention to act as an A_(2B) adenosinereceptor antagonists may be determined using pharmacological modelswhich are well known to the art or using test procedures describedbelow.

The rat A_(2B) receptor cDNA was subcloned into the expression plasmidpDoubleTrouble using techniques described in Robeva, A. et al., Biochem.Pharmacol., 51, 545-555 (1996). The plasmid was amplified in competentJM109 cells and plasmid DNA isolated using Wizard Megaprep columns(Promega Corporation, Madison, Wis.). A_(2B) adenosine receptors wereintroduced into HEK-293 cells by means of Lipofectin as described inFelgner, P. L. et al., Proc. Natl. Acad. Sci. USA, 84, 7413-7417 (1987).

Cell Culture

Transfected HEK cells were grown under 5% CO₂/95% O₂ humidifiedatmosphere at a temperature of 37° C. Colonies were selected by growthof cells in 0.6 mg/mL G418. Transfected cells were maintained in DMEMsupplemented with Hams F12 nutrient mixture (1/1), 10% newborn calfserum, 2 mM glutamine and containing 50 IU/mL penicillin, 50 mg/mLstreptomycin, and 0.2 mg/mL Geneticin (G418, Boehringer Mannheim). Cellswere cultured in 10 cm diameter round plates and subcultured when grownconfluent (approximately after 72 hours).

Radioligand Binding Studies

At A_(2B) receptors: Confluent monolayers of HEK-A_(2B) cells werewashed with PBS followed by ice cold Buffer A (10 mM HEPES, 10 mM EDTA,pH 7.4) with protease inhibitors (10 μg/mL benzamidine, 100 μMphenylmethanesulfonyl fluoride, and 2 μg/mL of each aprotinin, pepstatinand leupeptin). The cells were homogenized in a Polytron (Brinkmann) for20 s, centrifuged at 30,000×g, and the pellets washed twice with bufferHE (10 mM HEPES, 1 mM EDTA, pH 7.4 with protease inhibitors). The finalpellet was resuspended in buffer HE, supplemented with 10% sucrose andfrozen in aliquots at −80° C. For binding assays membranes were thawedand diluted 5-10 fold with HE to a final protein concentration ofapproximately 1 mg/mL. To determine protein concentrations, membranes,and bovine serum albumin standards were dissolved in 0.2% NaOH/0.01% SDSand protein determined using fluorescamine fluorescence. Stowell, C. P.et al., Anal. Biochem., 85, 572-580 (1978).

Saturation binding assays for rat A_(2B) adenosine receptors wereperformed with [³H]ZM214,385 (17 Ci/mmol, Tocris Cookson, Bristol UK)(Ji, X. et al., Drug Design Discov., 16, 216-226 (1999)) or ¹²⁵I-ABOPX(2200 Ci/mmol). To prepare ¹²⁵I-ABOPX, 10 μL of 1 mM ABOPX in methanol/1M NaOH (20:1) was added to 50 μL of 100 mM phosphate buffer, pH 7.3. Oneor 2 mCi of Na¹²⁵I was added, followed by 10 μL of 1 mg/mL chloramine-Tin water. After incubation, 20 minutes at room temperature, 50 μL of 10mg/mL Na-metabisulfite in water was added to quench the reaction. Thereaction mixture was applied to a C18 HPLC column, eluting with amixture of methanol and 5 mM phosphate, pH 6.0. After 5 min at 35%methanol, the methanol concentration was ramped to 100% over 15 min.Unreacted ABOPX eluted in 11-12 minutes; ¹²⁵I-ABOPX eluted at 18-19 minin a yield of 50-60% with respect to the initial ¹²⁵I.

In equilibrium binding assays the ratio of ¹²⁷I/¹²⁵I-ABOPX was 10-20/1.Radioligand binding experiments were performed in triplicate with 20-25μg membrane protein in a total volume of 0.1 mL HE buffer supplementedwith 1 U/mL adenosine deaminase and 5 mM MgCl₂. The incubation time was3 h at 21° C. Nonspecific binding was measured in the presence of 100 μMNECA. Competition experiments were carried out using 0.6 nM ¹²⁵I-ABOPX.Membranes were filtered on Whatman GF/C filters using a Brandel cellharvester (Gaithersburg, Md.) and washed 3 times over 15-20 seconds withice cold buffer (10 mM Tris, 1 mM MgCl₂, pH 7.4). B_(max) and K_(D)values were calculated by Marquardt's nonlinear least squaresinterpolation for single a site binding models. Marquardt, D. M., J.Soc. Indust. Appl. Math., 11, 431-441.21 (1963). K_(i) values fordifferent compounds were derived from IC₅₀ values as described. Linden,J., J. Cycl. Nucl. Res., 8, 163-172 (1982). Data from replicateexperiments are tabulated as means±SEM.

At other Adenosine Receptors: [³H]CPX. Bruns, R. F. et al.,Naunyn-Schmiedeberg's Arch. Pharmacol. 335, 59-63 (1987). ¹²⁵I-ZM241385and ¹²⁵I-ABA were utilized in radioligand binding assays to membranesderived from HEK-293 cells expressing recombinant rat A₁, A_(2A) and A₃ARs, respectively. Binding of [³H]R-N⁶-phenylisopropyladenosine.Schwabe, U. et al., Naunyn-Schmiedeberg's Arch. Pharmacol., 313, 179-187(1980). ([³H]R-PIA, Amersham, Chicago, Ill.) to A₁ receptors from ratcerebral cortical membranes and of [³H]CGS 21680. Jarvis, M. F. et al.,J. Pharmacol. Exp. Therap., 251, 888-893 (1989). (Dupont NEN, Boston,Mass.) to A_(2A) receptors from rat striatal membranes was performed asdescribed. Adenosine deaminase (3 units/mL) was present during thepreparation of the brain membranes, in a pre-incubation of 30 min at 30°C., and during the incubation with the radioligands. All non-radioactivecompounds were initially dissolved in DMSO, and diluted with buffer tothe final concentration, where the amount of DMSO never exceeded 2%.Incubations were terminated by rapid filtration over Whatman GF/Bfilters, using a Brandell cell harvester (Brandell, Gaithersburg, Md.).The tubes were rinsed three times with 3 mL buffer each.

At least six different concentrations of competitor, spanning 3 ordersof magnitude adjusted appropriately for the IC₅₀ of each compound, wereused. IC₅₀ values, calculated with the nonlinear regression methodimplemented in (Graph-Pad Prism, San Diego, Calif.), were converted toapparent K_(i) values as described. Linden, J., J. Cycl. Nucl. Res.,8:163-172 (1982). Hill coefficients of the tested compounds were in therange of 0.8 to 1.1.

Functional Assay

HEK-A_(2B) cells from one confluent T75 flask were rinsed with Ca²⁺ andMg²⁺-free Dulbecco's phosphate buffered saline (PBS) and then incubatedin Ca²⁺ and Mg²⁺-free HBSS with 0.05% trypsin and 0.53 mM EDTA until thecells detached. The cells were rinsed twice by centrifugation at 250×gin PBS and resuspended in 10 mL of HBSS composed of 137 mM NaCl, 5 mMKCl, 0.9 mM MgSO₄, 1.4 mM CaCl₂, 3 mM NaHCO₃, 0.6 mM Na₂HPO₄, 0.4 mMKH₃PO₄, 5.6 mM glucose, and 10 mM HEPES, pH 7.4 and the Ca²⁺-sensitivefluorescent dye indo-1-AM (5 μM) 37° C. for 60 min. The cells wererinsed once and resuspended in 25 mL dye-free HBSS supplemented with 1U/ml adenosine deaminase and held at room temperature. Adenosinereceptor antagonists prepared as 100× stocks in DMSO or vehicle wasadded and the cells and transferred to a 37° C. bath for 2 minutes. Thenthe cells (1 million in 2 ml) were transferred to a stirred cuvettemaintained at 37° C. within an Aminco SLM 8000 spectrofluorometer (SMLinstruments, Urbana Ill.). The ratios of indo-1 fluorescence obtained at400 and 485 nm (excitation, 332 nm) was recorded using a slit width of 4nm. NECA was added after a 100 s equilibration period.

Cyclic AMP Accumulation

Cyclic AMP generation was performed in DMEM/HEPES buffer (DMEMcontaining 50 mM HEPES, pH 7.4, 37° C.). Each well of cells was washedtwice with DMEM/HEPES buffer, and then 100 μL adenosine deaminase (finalconcentration 10 IU/mL) and 100 μL of solutions of rolipram andcilostamide (each at a final concentration of 10 μM) were added,followed by 50 μL of the test compound (appropriate concentration) orbuffer. After 15 minutes, incubation at 37° C. was terminated byremoving the medium and adding 200 ρL of 0.1 M HCl. Acid extracts werestored at −20° C. until assay. The amounts of cyclic AMP were determinedfollowing a protocol which utilized a cAMP binding protein (PKA) [vander Wenden et al., 1995], with the following minor modifications. Theassay buffer consisted of 150 mM K₂HPO₄/10 mM EDTA/0.2% BSA FV at pH7.5. Samples (20 mL) were incubated for 90 minutes at 0° C. Incubateswere filtered over GF/C glass microfiber filters in a Brandel M-24 CellHarvester. The filters were additionally rinsed with 4 times 2 mL 150 mMK₂HPO₄/10 mM EDTA (pH 7.5, 4° C.). Punched filters were counted inPackard Emulsifier Safe scintillation fluid after 2 hours of extraction.

Representative compounds of the present invention have been shown to beactive in the above affinity testing.

Proton nuclear magnetic resonance spectroscopy was performed on aVarian-300 MHz spectrometer and spectra were taken in DMSO-d₆. Unlessnoted, chemical shifts are expressed as ppm downfield from relative ppmfrom DMSO (2.5 ppm). Electro-spray-ionization (ESI) mass spectrometrywas performed with a ThermoFinnigan LCQ mass spectrometer.

All xanthine derivatives were homogeneous as judged using TLC (Silicagel 60 F₂₅₄, 0.25 mm, aluminum backed, EM Science, Gibbstown, N.J.) andHPLC (Shimadzu) using Varian C18 5 micron analytical column (4.6 mm×150mm) in linear gradient solvent system, at a flow rate of 1 mL/min. Thesolvent system used was MeOH (0.1% formic acid):H₂O (0.1% formic acid).Peaks were detected by UV absorption at 300 nm and 254 nm. NMR and massspectra were shown to be consistent with the assigned structure.

General Procedures for the Preparation of Chloro Substituted PyridylCompounds A

6-Chloronicotinoyl chloride, prepared from 6-hydroxynicotinic acid(1.444 g, 10.4 mmol), in CH₂Cl₂ (20 mL) was added dropwise to a solutionof 5,6-diamino-1,3-disubstituteduracil (8 mmol) in dry pyridine (8.2 mL)maintained at 5° C. The reaction was warmed to room temperature andstirred for an additional 3 hours. Water (50 mL) was added to quench thereaction. The solvent was evaporated to afford a dark colored oil. Theoil was refluxed for 2 h in 2N NaOH (20 mL). After cooling, the pH wascarefully adjusted to 7 with concentrated HCl. A solid formed and wascollected and washed with water (20 mL), ether (20 mL) and chloroform(20 mL) to provide an off-white solid. The product was used in the nextstep without further purification.

1A: 1,3-Dipropyl-8-(6-chloro-3-pyridyl)xanthine

¹H NMR (DMSO, d₆): δ 0.89 (m, 6H), 1.59 (m, 2H), 1.73 (m, 2H), 3.88 (t,2H, J=7.2 Hz), 4.00 (t, 2H, J=7.2 Hz), 7.68 (d, 1H, J=8.4 Hz), 8.50 (dd,1H, J₁=2.4 Hz, J₂=8.4 Hz), 9.07 (d, 1H, J=2.4 Hz).

MS: m/z 348 (M+H)⁺.

2A: 1-Cyclopropyl-3-propyl-8-(6-chloro-3-pyridyl)xanthine

¹H NMR (DMSO, d₆): δ 0.72 (m, 2H), 0.91 (t, 3H, J=7.8 Hz), 1.03 (m, 2H),1.72 (m, 2H), 2.63 (m, 1H), 3.98 (t, 2H, J=7.8 Hz), 7.68 (d, 1H, J=8.4Hz), 8.46 (dd, 1H, J₁=2.4 Hz, J₂=8.4 Hz), 9.07 (d, 1H, J=2.4 Hz).

MS: m/z 346 (M+H)⁺.

3A: 1,3-Diallyl-8-(6-chloro-3-pyridyl)xanthine

¹H NMR (DMSO, d₆): 4.56 (d, 2H, J=5.1 Hz), 4.70 (d, 2H, J=5.1 Hz), 5.15(m, 4H), 5.98 (m, 2H), 7.74 (d, 1H, J=8.4 Hz), 8.50 (dd, 1H, J₁=2.4 Hz,J₂=8.4 Hz), 9.12 (d, 1H, J=2.4 Hz).

MS: m/z 344 (M+H)⁺.

General Procedures for the Preparation of Amino Substituted PyridylCompounds B

Compound A (40 mg) and the corresponding substituted amine (0.5 mL or0.5 g) were put in a pressure tube. (Ethanol, 4 mL, was added as thesolvent if the amine is a solid.) The pressure tube was flushed withargon, sealed and stirred at 160° C. for 48-60 h. After cooling, ether(10 mL) was added. The resulting solid was collected and purified bysilica gel column or preparative TLC (Solvent A: CH₂Cl₂:MeOH=20:1 to10:1 or Solvent B:CH₂Cl₂:MeOH:TEA=20:1:0.1 to 4:1:0.1).

1B: 1-Cyclopropyl-3-propyl-8-[6-methylamino-3-pyridyl]xanthine

¹H NMR (DMSO, d₆): 0.72 (m, 2H), 0.91 (t, 3H, J=7.5 Hz), 1.03 (m, 2H),1.71 (m, 2H), 2.62 (m, 1H), 2.81 (d, 3H, J=4.5 Hz), 3.96 (t, 2H, J=7.5Hz), 6.52 (d, 1H, J=9.0 Hz), 7.07 (d, 1H, J=4.5 Hz), 8.01 (dd, 1H,J₁=2.4 Hz, J₂=9.0 Hz), 8.73 (d, 1H, J=2.4 Hz).

MS: m/z 341 (M+H)⁺.

2B: 1,3-Dipropyl-8-[6-(2-methoxyethyl)amino-3-pyridyl]xanthine

¹H NMR (DMSO, d₆): δ 0.93 (m, 6H), 1.63 (m, 2H), 1.78 (m, 2H), 3.38 (s,3H), 3.53 (s, 4H), 3.91 (t, 2H, J=7.5 Hz), 4.05 (t, 2H, J=7.5 Hz), 6.65(d, 1H, J=8.7 Hz), 7.24 (s(br), 1H), 8.06 (dd, 1H, J₁=2.4 Hz, J₂=8.7Hz), 8.71 (d, 1H, J=2.4 Hz).

MS: m/z 387 (M+H)⁺.

3B: 1-Cyclopropyl-3-propyl-8-[6-(2-methoxyethyl)amino-3-pyridyl]xanthine

¹H NMR (DMSO, d₆): 0.74 (m, 2H), 0.94 (t, 3H, J=7.5 Hz), 1.06 (m, 2H),1.75 (m, 2H), 2.65 (m, 1H), 3.32 (s, 3H), 3.52 (s, 4H), 4.00 (t, 2H,J=7.5 Hz), 6.64 (d, 1H, J=8.7 Hz), 7.23 (s(br), 1H), 8.04 (dd, 1H,J₁=2.4 Hz, J₂=8.7 Hz), 8.76 (d, 1H, J=2.4 Hz).

MS: m/z 385 (M+H)⁺.

4B: 1,3-Diallyl-8-[6-(2-methoxyethyl)amino-3-pyridyl]xanthine

¹H NMR (DMSO, d₆): 3.32 (s, 3H), 3.52 (s, 4H), 4.55 (d, 2H, J=5.1 Hz),4.68 (d, 2H, J=5.1 Hz), 5.15 (m, 4H), 5.95 (m, 2H), 6.64 (d, 1H, J=9.0Hz), 7.25 (s(br), 1H), 8.05 (dd, 1H, J₁=2.4 Hz, J₂=9.0 Hz), 8.77 (d, 1H,J=2.4 Hz).

MS: m/z 383 (M+H)⁺.

5B:1-Cyclopropyl-3-propyl-8-[6-(2-morpholinoethyl)amino-3-pyridyl]xanthine

¹H NMR (DMSO, d₆): 0.74 (m, 2H), 0.94 (t, 3H, J=7.5 Hz), 1.06 (m, 2H),1.75 (m, 2H), 2.46 (t, 4H, J=4.5 Hz), 2.52 (m, 2H), 2.65 (m, 1H), 3.46(m, 2H), 3.63 (t, 4H. J=4.5 Hz), 4.00 (t, 2H, J=7.2 Hz), 6.62 (d, 1H,J=8.7 Hz), 7.23 (t, 1H, J=5.4 Hz), 8.04 (dd, 1H, J₁=2.4 Hz, J₂=8.7 Hz),8.75 (d, 1H, J=2.4 Hz).

MS: m/z 440 (M+H)⁺.

6B:1-Cyclopropyl-3-propyl-8-[6-(2-(piperidin-1-yl)ethylamino)-3-pyridyl]xanthine

¹H NMR (DMSO, d₆): 0.74 (m, 2H), 0.94 (t, 3H, J=7.5 Hz), 1.07 (m, 2H),1.44 (m, 2H), 1.57 (m, 4H), 1.75 (m, 2H), 2.51 (m, 6H), 2.65 (m, 1H),3.48 (m, 2H), 4.00 (t, 2H, J=7.2 Hz), 6.63 (d, 1H, J=9.0 Hz), 7.05 (t,1H), 8.05 (dd, 1H, J₁=2.4 Hz, J₂=9.0 Hz), 8.76 (d, 1H, J=2.4 Hz).

MS: m/z 438 (M+H)⁺.

7B:1-Cyclopropyl-3-propyl-8-[6-(2-(pyrrolidin-1-yl)ethylamino)-3-pyridyl]xanthine

MS: m/z 424 (M+H)⁺.

General Procedures for the Preparation of Amide Compounds (1-33)

The amino substituted pyridyl compound B (50 mg) was dissolved inpyridine (25 mg) at 80-100° C. After cooling to room temperature, thedesired acid chloride (4-6 equivalents) was added at room temperature.The mixture was stirred at room temperature for 24-60 h. The reactionwas quenched with ice and the solvent was removed and the residue waspurified by silica gel column (CH₂Cl₂:MeOH=96:4) to give compound 1-36and 46-51 at 60-80% yield.

1:1-Cyclopropyl-3-propyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-methylamino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes, then MeOH 95%.Retention Time=9.77 min.

¹H NMR (DMSO, d₆): 0.72 (m, 2H), 0.89 (t, 3H, J=7.5 Hz), 1.01 (m, 2H),1.71 (m, 2H), 2.62 (m, 1H), 3.53 (s, 3H), 3.96 (t, 2H, J=7.5 Hz), 7.53(d, 1H, J=8.4 Hz,), 7.88 (d, 1H, J=8.4 Hz,), 8.00 (dd, 1H, J₁=1.8 Hz,J₂=7.8 Hz), 8.38 (dd, 1H, J₁=2.4 Hz, J₂=8.4 Hz), 8.70 (s, 1H), 8.94 (d,1H, J=2.4 Hz).

MS: m/z 514 (M+H)⁺.

2:1-Cyclopropyl-3-propyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-ethylamino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=10.13 min.

¹H NMR (DMSO, d₆): 0.70 (m, 2H), 0.88 (t, 3H, J=7.5 Hz), 1.02 (m, 2H),1.19 (3H, J=7.2 Hz), 1.69 (m, 2H), 2.61 (m, 1H), 3.95 (t, 2H, J=7.2 Hz),4.08 (q, 2H, J=7.5 Hz), 7.46 (d, 1H, J=8.7 Hz), 7.85 (d, 1H, J=8.1 Hz),7.96 (dd, 1H, J₁=8.1 Hz, J₂=2.1 Hz), 8.36 (dd, 1H, J₁=8.7 Hz, J₂=2.1Hz), 8.66 (s, 1H), 8.96 (d, 1H, J=2.1 Hz).

MS: m/z 528 (M+H)⁺.

3:1-Cyclopropyl-3-propyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-propylamino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=10.80 min.

¹H NMR (DMSO, d₆): ¹H NMR (DMSO, d₆): □ 0.71 (m, 2H), 0.91 (m, 6H), 1.03(m, 2H), 1.57-1.73 (m, 4H), 2.61 (m, 1H), 3.92-4.04 (m, 4H), 7.47 (d,1H, J=8.7 Hz), 7.85 (d, 1H, J=8.4 Hz), 7.95 (d, 1H, J=8.4 Hz), 8.36 (dd,1H, J₁=8.7 Hz, J₂=2.4 Hz), 8.66 (s, 1H), 8.95 (d, 1H, J=2.4 Hz).

MS: m/z 542 (M+H)⁺.

4:1-Cyclopropyl-3-propyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-(2-methoxyethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=10.08 min.

¹H NMR (DMSO, d₆): ¹H NMR (DMSO, d₆): 0.71 (m, 2H), 0.88 (t, 3H, J=7.5Hz), 1.05 (m, 2H), 1.70 (m, 2H), 2.62 (m, 1H), 3.19 (s, 3H), 3.62 (t,2H, J=5.4 Hz), 3.96 (t, 2H, J=7.5 Hz), 4.21 (t, 2H, J=5.4 Hz), 7.47 (d,1H, J=8.7 Hz), 7.87 (d, 1H, J=8.1 Hz), 7.96 (d, 1H, J=8.1 Hz), 8.34 (dd,1H, J₁=8.7 Hz, J₂=2.4 Hz), 8.66 (s, 1H), 8.95 (d, 1H, J=2.4 Hz).

MS: m/z 558 (M+H)⁺.

5:1-Cyclopropyl-3-propyl-8-[6-(N-(6-fluoronicotinoyl)-N-(2-methoxyethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=9.32 min.

¹H NMR (DMSO, d₆): 0.74 (m, 2H), 0.92 (t, 3H, J=7.5 Hz), 1.06 (m, 2H),1.73 (m, 2H), 2.65 (m, 1H), 3.19 (s, 3H), 3.64 (t, 2H, J=5.7 Hz), 3.99(t, 2H, J=7.5 Hz), 4.22 (t, 2H, J=5.7 Hz), 7.18 (dd, 1H, J₁=8.4 Hz,J₂=2.4 Hz), 7.41 (d, 1H, J=8.4 Hz), 7.91 (td, 1H, J₁=8.4 Hz, J₂=2.4 Hz),8.18 (d, 1H, J=2.4 Hz), 8.36 (dd, 1H, J₁=8.4 Hz, J₂=2.1 Hz), 8.76 (d,1H, J=2.1 Hz).

MS: m/z 508 (M+H)⁺.

6:1-Cyclopropyl-3-propyl-8-[6-(N-nicotinoyl-N-(2-methoxyethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=8.53 min.

MS: m/z 490 (M+H)⁺.

7:1-Cyclopropyl-3-propyl-8-[6-(N-nicotinoyl-N-(cyclopropylmethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=9.77 min.

MS: m/z 486 (M+H)⁺.

8:1-Cyclopropyl-3-propyl-8-[6-(N-nicotinoyl-N-(cyclopropyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=8.67 min.

MS: m/z 472 (M+H)⁺.

9:1-Cyclopropyl-3-propyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-(cyclopropylmethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=10.71 min.

¹H NMR (DMSO, d₆): 0.19 (m, 2H), 0.41 (m, 2H), 0.72 (m, 2H), 0.91 (t,3H, J=7.2 Hz), 1.00-1.16 (m, 3H), 1.70 (m, 2H), 2.62 (m, 1H), 3.96 (m,4H), 7.47 (d, 1H, J=8.4 Hz), 7.86 (d, 1H, J=8.1 Hz,), 7.97 (dd, 1H,J₁=2.1 Hz, J₂=8.1 Hz), 8.36 (dd, 1H, J₁=2.1 Hz, J₂=8.4 Hz), 8.68 (s,1H), 8.98 (d, 1H, J=2.1 Hz).

MS: m/z 554 (M+H)⁺.

10:1-Cyclopropyl-3-propyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-(tetrahydrofuranylmethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=10.31 min.

¹H NMR (DMSO, d₆): 0.71 (m, 2H), 0.88 (t, 3H, J=7.5 Hz), 1.02 (m, 2H),1.54-1.96 (m, 6H), 2.61 (m, 1H), 3.57 (dt, 2H, J₁=6.9 Hz, J₂=3.0 Hz),3.96 (t, 2H, J=7.2 Hz), 4.04-4.18 (m, 3H), 7.48 (d, 1H, J=8.4 Hz), 7.85(d, 1H, J=8.4 Hz), 7.95 (dd, 1H, J₁=8.4 Hz, J₂=2.4 Hz), 8.34 (dd, 1H,J₁=8.4 Hz, J₂=2.4 Hz), 8.66 (s, 1H), 8.93 (d, 1H, J=2.4 Hz).

MS: m/z 584 (M+H)⁺.

11:1-Cyclopropyl-3-propyl-8-[6-(N-nicotinoyl-N-ethylamino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=8.93 min.

¹H NMR (DMSO, d₆): 0.72 (m, 2H), 0.91 (t, 3H, J=7.2 Hz), 1.04 (m, 2H),1.19 (t, 3H, J=7.2 Hz), 1.70 (m, 2H), 2.61 (m, 1H), 3.95 (t, 2H, J=7.2Hz), 4.06 (q, 2H, J=7.2 Hz), 7.33 (m, 2H), 7.80 (dt, 1H, J₁=1.5 Hz,J₂=8.1 Hz,), 8.31 (dd, 1H, J₁=2.4 Hz, J₂=8.4 Hz), 8.44 (d, 1H, J=2.1),8.53 (dd, 1H, J₁=2.1 Hz, J₂=4.8 Hz), 8.99 (d, 1H, J=2.1 Hz).

MS: m/z 460 (M+H)⁺.

12:1-Cyclopropyl-3-propyl-8-[6-(N-nicotinoyl-N-propylamino)-3-pyridyl]xanthine

¹H NMR (DMSO, d₆): 0.72 (m, 2H), 0.88 (t, 6H, J=7.5 Hz), 1.02 (m, 2H),1.57-1.74 (m, 4H), 2.62 (m, 1H), 3.97 (m, 4H), 7.31 (dd, 1H, J₁=7.8 Hz,J₂=0.9 Hz), 7.34 (d, 1H, J=8.7 Hz), 7.68 (dt, 1H, J₁=7.8 Hz, J₂=1.8Hz,), 8.30 (dd, 1H, J₁=8.4 Hz, J₂=2.4 Hz), 8.42 (d, 1H, J=2.4 Hz), 8.51(dd, 1H, J₁=4.8 Hz, J₂=1.5 Hz), 8.99 (d, 1H, J=2.4 Hz).

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%:Retention Time=9.7 min.

MS: m/z 474 (M+H)⁺.

13:1-Cyclopropyl-3-propyl-8-[6-(N-[6-fluoronicotinoyl]-N-[cyclopropylmethyl]amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=10.09 min.

¹H NMR (DMSO, d₆): 0.15 (m, 2H), 0.39 (m, 2H), 0.72 (m, 2H), 0.89 (t,3H, J=7.5 Hz), 1.00-1.20 (m, 3H), 1.71 (m, 2H), 2.63 (m, 1H), 3.95 (m,4H), 7.13 (dd, 1H, J₁=8.4 Hz, J₂=2.1 Hz), 7.37 (d, 1H, J=8.4 Hz), 7.88(m, 1H), 8.16 (s, 1H), 8.33 (dd, 1H, J₁=8.4 Hz, J₂=2.1 Hz), 9.00 (d, 1H,J=2.1 Hz).

MS: m/z 504 (M+H)⁺.

14:1-Cyclopropyl-3-propyl-8-[6-(N-[6-fluoronicotinoyl]-N-methylamino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=9.00 min.

¹H NMR (DMSO, d₆): 0.72 (m, 2H), 0.90 (t, 3H, J=7.5 Hz), 1.03 (m, 2H),1.72 (m, 2H), 2.63 (m, 1H), 3.51 (s, 3H), 3.97 (t, 2H, J=7.5 Hz), 7.17(dd, 1H, J₁=8.1 Hz, J₂=2.1 Hz), 7.45 (d, 1H, J=8.4 Hz,), 7.93 (m, 1H),8.20 (s, 1H), 8.36 (dd, 1H, J₁=7.5 Hz, J₂=2.1 Hz), 8.99 (s, 1H).

MS: m/z 464 (M+H)⁺.

15:1-Cyclopropyl-3-propyl-8-[6-(N-nicotinoyl-N-allylamino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=9.28 min.

¹H NMR (DMSO, d₆): ¹H NMR (DMSO, d₆): □ 0.71 (m, 2H), 0.88 (t, 3H, J=7.5Hz), 1.03 (m, 2H), 1.68 (m, 2H), 2.61 (m, 1H), 3.95 (t, 2H, J=7.2 Hz),4.67 (d, 2H, J=4.5 Hz), 5.16 (m, 2H), 5.92 (m, 1H), 7.37 (m, 2H), 7.73(d, 1H, J=7.8 Hz), 8.32 (d, 1H, J=8.7 Hz), 8.48 (s, 1H), 8.54 (d, 1H,J=3.9 Hz), 9.0 (s, 1H).

MS: m/z 472 (M+H)⁺.

16:1-Cyclopropyl-3-propyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-allylamino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=10.37 min.

¹H NMR (DMSO, d₆): ¹H NMR (DMSO, d₆): 0.73 (m, 2H), 0.91 (t, 3H, J=7.5Hz), 1.03 (m, 2H), 1.72 (m, 2H), 2.66 (m, 1H), 3.99 (t, 2H, J=7.2 Hz),4.73 (d, 2H, J=4.8 Hz), 5.15-5.30 (m, 2H), 5.91-6.00 (m, 1H), 7.53 (d,2H, J=8.4 Hz), 7.91 (d, 1H, J=8.1 Hz), 8.03 (d, 1H, J=8.1 Hz), 8.40 (dd,1H, J₁=8.4 Hz, J₂=2.1 Hz), 8.73 (s, 1H), 8.95 (d, 1H, J=2.1 Hz).

MS: m/z 540 (M+H)⁺.

17:1-Cyclopropyl-3-propyl-8-[6-(N-nicotinoyl-N-(2-[piperidin-1-yl]ethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=4.90 min.

MS: m/z 543 (M+H)⁺.

18:1-Cyclopropyl-3-propyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-(2-[piperidin-1-yl]ethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=6.63 min.

MS: m/z 611 (M+H)⁺.

19:1-Cyclopropyl-3-propyl-8-[6-(N-nicotinoyl-N-(2-morpholinoethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 20%-70% gradient in 10 minutes then MeOH 70%.Retention Time=9.44 min.

MS: m/z 545 (M+H)⁺.

20:1-Cyclopropyl-3-propyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-(2-morpholinoethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=6.36 min.

¹H NMR (DMSO, d₆): 0.73 (m, 2H), 0.91 (t, 3H, J=7.5 Hz), 1.05 (m, 2H),1.73 (m, 2H), 2.36 (m, 4H), 2.63 (m, 3H), 3.39 (m, 4H), 3.99 (t, 2H,J=7.5 Hz), 4.20 (t, 2H, J=6.0 Hz), 7.43 (d, 1H, J=8.4 Hz), 7.90 (d, H,J=8.1 Hz), 8.00 (d, 1H, J=8.1 Hz), 8.34 (dd, 1H, J₁=8.4 Hz, J₂=2.4 Hz),8.70 (s, 1H), 8.99 (d, 1H, J=2.4 Hz).

MS: m/z 613 (M+H)⁺.

21:1-Cyclopropyl-3-propyl-8-[6-(N-[6-fluoronicotinoyl]-N-(2-[piperidin-1-yl]ethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 20%-52% gradient in 10 minutes then MeOH 52%.Retention Time=13.9 min.

¹H NMR (DMSO, d₆): 0.74 (m, 2H), 0.92 (t, 3H, J=7.5 Hz), 1.06 (m, 2H),1.45-1.84 (m, 8H), 2.65 (m, 1H), 2.99 (m, 2H), 3.35 (m, 2H), 3.59 (m,2H), 3.99 (t, 2H, J=7.5 Hz), 4.45 (m, 2H), 7.20 (dd, 1H, J₁=8.4 Hz,J₂=2.4 Hz), 7.43 (d, 1H, J=8.4 Hz), 7.97 (dt, 1H, J₁=8.1 Hz, J₂=2.4 Hz),8.23 (d, H, J=2.4 Hz), 8.35 (dd, 1H, J₁=8.4 Hz, J₂=2.4 Hz), 9.12 (d, 1H,J=2.4 Hz), 10.13 (s, 1H).

MS: m/z 561 (M+H)⁺.

22:1-Cyclopropyl-3-propyl-8-[6-(N-[6-fluoronicotinoyl]-N-(2-morpholinoethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 20%-70% gradient in 10 minutes then MeOH 70%.Retention Time=10.13 min.

¹H NMR (DMSO, d₆): 0.73 (m, 2H), 0.89 (t, 3H, J=7.5 Hz), 1.03 (m, 2H),1.73 (m, 2H), 2.34 (m, 4H), 2.62 (m, 3H), 3.39 (m, 4H), 3.96 (t, 2H,J=7.5 Hz), 4.16 (m, 2H), 7.14 (dd, 1H, J₁=8.7 Hz, J₂=2.4 Hz), 7.31 (d,1H, J=8.7 Hz), 7.89 (td, J₁=8.4 Hz, J₂=2.4 Hz), 8.16 (d, 1H, J=2.4 Hz),8.29 (dd, 1H, J₁=8.7 Hz, J₂=2.4 Hz), 9.00 (s, 1H).

MS: m/z 563 (M+H)⁺.

23:1-Cyclopropyl-3-propyl-8-[6-(N-nicotinoyl-N-(2-[pyrrolidin-1-yl]ethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=4.62 min.

MS: m/z 529 (M+H)⁺.

24:1-Cyclopropyl-3-propyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-(2-[pyrrolidin-1-yl]ethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=6.43 min.

MS: m/z 597 (M+H)⁺.

25:1-Cyclopropyl-3-propyl-8-[6-[(N-nicotinoyl-N-[(thiophen-2-yl)methyl]amino)]-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=10.10 min.

MS: m/z 528 (M+H)⁺.

26:1-Cyclopropyl-3-propyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-iso-butylamino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=11.06 min.

¹H NMR (DMSO, d₆): 0.71 (m, 2H), 0.88 (m, 9H), 1.02 (m, 2H), 1.68 (m,2H), 1.91 (m, 1H), 2.61 (m, 1H), 3.95 (m, 4H), 7.48 (d, 1H, J=8.4 Hz),7.83 (d, 1H, J=8.4 Hz), 7.92 (d, 1H, J=8.1 Hz), 8.35 (dd, 1H, J₁=8.4 Hz,J₂=2.1 Hz), 8.64 (s, 1H), 8.94 (d, 1H, J=2.1 Hz).

MS: m/z 556 (M+H)⁺.

27:1,3-Dipropyl-8-[6-(N-nicotinoyl-N-(cyclopropylmethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=10.63 min.

¹H NMR (DMSO, d₆): 0.18 (m, 2H), 0.42 (m, 2H), 0.89 (m, 6H), 1.15 (m,1H), 1.60 (m, 2H), 1.74 (m, 2H), 3.87 (t, 2H, J=7.2 Hz), 4.01 (m, 4H),7.34 (m, 2H), 7.71 (d, 1H, J=7.8 Hz), 8.31-8.54 (m, 3H), 8.69 (s, 1H).

MS: m/z 488 (M+H)⁺.

28:1,3-Dipropyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-(cyclopropylmethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=11.46 min.

¹H NMR (DMSO, d₆): 0.18 (m, 2H), 0.42 (m, 2H), 0.89 (m, 6H), 1.16 (m,1H), 1.60 (m, 2H), 1.74 (m, 2H), 3.87 (t, 2H, J=7.2 Hz), 4.01 (m, 4H),7.49 (d, 1H, J=8.4 Hz), 7.87 (d, 1H, J=8.4 Hz), 7.97 (d, 1H, J=8.4 Hz),8.38 (dd, 1H, J₁=8.4 Hz, J₂=2.4 Hz), 8.69 (s, 1H), 9.00 (d, 1H, J=2.4Hz).

MS: m/z 556 (M+H)⁺.

29:1,3-Dipropyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-(2-methoxyethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=10.91 min.

¹H NMR (DMSO, d₆): 0.87 (m, 6H), 1.60 (m, 2H), 1.73 (m, 2H), 3.19 (s,3H), 3.62 (t, 3H, J=5.1 Hz), 3.86 (t, 2H, J=7.2 Hz), 4.00 (t, 2H, J=7.2Hz), 4.31 (t, 2H, J=5.1 Hz), 7.48 (d, 1H, J=8.4 Hz), 7.87 (d, 1H, J=8.4Hz),), 7.96 (d, 1H, J=8.4 Hz), 8.36 (dd, 1H, J₁=8.4 Hz, J₂=2.4 Hz), 8.66(s, 1H), 8.95 (d, 1H, J=2.4 Hz).

MS: m/z 560 (M+H)⁺.

30:1,3-Dipropyl-8-[6-(N-(6-fluoronicotinoyl)-N-(2-methoxyethyl)amino)-3-pyridyl]xanthine

¹H NMR (DMSO, d₆): 0.88 (m, 6H), 1.57 (m, 2H), 1.72 (m, 2H), 3.18 (s,3H), 3.60 (t, 2H, J=5.7 Hz), 3.86 (t, 2H, J=7.5 Hz), 4.00 (t, 2H, J=7.5Hz), 4.19 (t, 2H, J=5.7 Hz), 7.14 (dd, 1H, J₁=8.7 Hz, J₂=2.7 Hz), 7.39(d, 1H, J=8.7 Hz,), 7.88 (dt, 1H, J₁=8.4 Hz, J₂=2.7 Hz), 8.15 (d, 1H,J=2.7 Hz), 8.34 (dd, 1H, J₁=8.4 Hz, J₂=2.4 Hz), 8.99 (d, 1H, J=2.4 Hz).

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%:Retention Time=10.18 min.

MS: m/z 510 (M+H)⁺.

31:1,3-Diallyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-(2-methoxyethyl)amino)-3-pyridyl]xanthine

¹H NMR (DMSO, d₆): 3.18 (s, 3H), 3.60 (t, 2H, J=5.4 Hz), 4.21 (t, 2H,J=5.4 Hz), 4.50 (d, 2H, J=4.5 Hz), 4.64 (d, 2H, J=4.5 Hz), 5.02-5.15 (m,4H), 5.83-6.00 (m, 2H), 7.48 (d, 1H, J=8.7 Hz), 7.86 (d, 1H, J=8.4 Hz,),7.95 (d, 1H, J=8.4 Hz), 8.35 (dd, 1H, J₁=8.4 Hz, J₂=2.4 Hz), 8.67 (d,1H, J=1.5 Hz), 8.95 (d, 1H, J=2.4 Hz).

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%:Retention Time=9.81 min.

MS: m/z 556 (M+H)⁺.

32:1,3-Diallyl-8-[6-(N-[6-fluoronicotinoyl]-N-(2-methoxyethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=9.00 min.

MS: m/z 506 (M+H)⁺.

33:1,3-Diallyl-8-[6-(N-nicotinoyl-N-(2-methoxyethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=8.28 min.

MS: m/z 488 (M+H)⁺.

34: 1,3-Dipropyl-8-[6-(N-piperazinyl)-3-pyridyl]xanthine

Compound 34 can be formed from compound 1A by condensation withpiperazine.

HPLC condition: MeOH 20%-75% gradient in 10 minutes then MeOH 75%.Retention Time=9.24 min.

¹H NMR (DMSO, d₆): 0.87 (q, 6H, J=7.5 Hz), 1.56 (m, 2H), 1.72 (m, 2H),2.78 (t, 4H, J=4.5 Hz), 3.52 (t, 4H, J=4.5 Hz), 3.85 (t, 2H, J=7.5 Hz),3.99 (t, 2H, J=7.5 Hz), 6.88 (d, 1H, J=9.0 Hz), 8.13 (dd, 1H, J₁=9.0 Hz,J₂=2.4 Hz), 8.80 (d, 1H, J=2.4 Hz).

MS: m/z 398 (M+H)⁺.

35:1,3-Dipropyl-8-[6-(N-(6-fluoronicotinoyl)-N-(methyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=10.01 min.

¹H NMR (DMSO, d₆): ¹H NMR (DMSO, d₆): 0.88 (m, 6H), 1.57 (m, 2H), 1.72(m, 2H), 3.50 (s, 3H), 3.86 (t, 2H, J=7.5 Hz), 4.00 (t, 2H, J=7.5 Hz),7.16 (dd, 1H, J₁=8.4 Hz, J₂=2.4 Hz), 7.45 (d, 1H, J=8.7 Hz), 7.92 (dt,1H, J₁=8.4 Hz, J₂=2.4 Hz), 8.19 (d, 1H, J=2.4 Hz), 8.36 (dd, 1H, J₁=8.7Hz, J₂=2.4 Hz), 8.99 (d, 1H, J=2.4 Hz).

MS: m/z 466 (M+H)⁺.

36:1,3-Dipropyl-8-[6-(N-[6-(trifluoromethyl)nicotinoyl]-N-(ethyl)amino)-3-pyridyl]xanthine

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=10.87 min.

¹H NMR (DMSO, d₆): 0.92 (m, 6H), 1.24 (t, 3H, J=6.9 Hz), 1.55-1.78 (m,4H), 3.90 (t, 2H, J=7.2 Hz), 4.03 (t, 2H, J=7.2 Hz), 4.12 (q, 2H, J=6.9Hz), 7.51 (d, 1H, J=8.4 Hz), 7.90 (d, 1H, J=8.4 Hz), 8.00 (dd, 1H,J₁=8.4 Hz, J₂=1.8 Hz), 8.41 (dd, 1H, J₁=8.4 Hz, J₂=2.1 Hz), 8.71 (s,1H), 9.01 (d, 1H, J=1.8 Hz).

¹³C NMR (DMSO, d₆): 10.95, 11.11, 13.10, 20.79, 20.78, 42.181, 43.12,44.46, 108.22, 120.26, 120.45, 120.97, 122.87, 135.71, 136.06, 137.75,146.44, 146.55, 147.00, 148.25, 149.03, 150.61, 154.08, 155.11, 166.48.

MS: m/z 530 (M+H)⁺.

General Procedures for the Preparation of Urea Substituted PyridylCompounds 37-41:

Compound B (50 mg) and the corresponding substituted isocyanate (3 eq)were placed in a pressure vessel and dissolved in dry THF (˜5-10 mls).The pressure vessel was flushed with nitrogen, sealed and stirred at 80°C. for 24-72 h. After cooling, the mixture was concentrated in vacuo andpurified by gradient silica gel chromatography or preparative HPLC.

37:1-(5-(1-cyclopropyl-2,3,6,7-tetrahydro-2,6-dioxo-3-propyl-1H-purin-8-yl)pyridin-2-yl)-1-(2-methoxyethyl)-3-(3-methoxyphenyl)urea

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=12.80 min.

MS: m/z 534 (M+H)⁺.

38:1-(5-(1-cyclopropyl-2,3,6,7-tetrahydro-2,6-dioxo-3-propyl-1H-purin-8-yl)pyridin-2-yl)-3-(3-fluorophenyl)-1-(2-methoxyethyl)urea

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=12.94 min.

¹H NMR (DMSO, d₆): 0.77 (m, 2H), 0.95 (t, 3H, J=7.2 Hz), 1.07 (d, 2H,J=6.3 Hz), 1.77 (d, 2H, J=6.9 Hz), 2.67 (m, 1H), 3.31 (s, 3H), 3.65 (t,2H, J=5.4 Hz), 4.03 (t, 2H, J=6.6 Hz), 4.23 (t, 2H, J=5.4 Hz), 6.91 (m,1H), 7.37 (m, 2H), 7.59 (m, 2H), 8.47 (d, 1H, J=8.7 Hz), 9.14 (s, 1H),11.20 (s, 1H).

MS: m/z 522 (M+H)⁺.

39:11-(5-(1-cyclopropyl-2,3,6,7-tetrahydro-2,6-dioxo-3-propyl-1H-purin-8-yl)pyridin-2-yl)-3-(2-fluorophenyl)-1-(2-methoxyethyl)urea

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=13.28 min.

MS: m/z 522 (M+H)⁺.

40:3-(3-chlorophenyl)-1-(5-(1-cyclopropyl-2,3,6,7-tetrahydro-2,6-dioxo-3-propyl-1H-purin-8-yl)pyridin-2-yl)-1-(2-methoxyethyl)urea

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=13.55 min.

¹H NMR (DMSO, d₆): 0.77 (m, 2H), 0.95 (t, 3H, J=7.2 Hz), 1.07 (m, 2H),1.77 (q, 2H, J=7.2 Hz), 2.67 (m, 1H), 3.30 (s, 3H), 3.65 (t, 2H, J=5.4Hz), 4.04 (t, 2H, J=6.3 Hz), 4.22 (t, 2H, J=5.4 Hz), 7.12 (dd, 1H, J=1.5Hz, 8.4 Hz), 7.37 (t, 2H, J=8.1 Hz), 7.55 (q, 2H, J=9.0 Hz), 7.80 (t,1H, J=2.1 Hz), 8.46 (dd, 1H, J₁=2.7 Hz, J₂=9.3 Hz), 9.15 (d, 1H, J=2.4Hz), 11.14 (s, 1H).

MS: m/z 538 (M+H)⁺.

41:1-(5-(1-cyclopropyl-2,3,6,7-tetrahydro-2,6-dioxo-3-propyl-1H-purin-8-yl)pyridin-2-yl)-3-(3-(trifluoromethyl)phenyl)-1-(2-methoxyethyl)urea

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=13.30 min.

¹H NMR (DMSO, d₆): 0.76 (m, 2H), 0.98 (t, 3H, J=7.2 Hz), 1.07 (q, 2H,J=7.2 Hz), 1.77 (q, 2H, J=7.2 Hz), 2.67 (m, 1H), 3.29 (s, 3H), 3.65 (t,2H, J=5.7 Hz), 4.04 (t, 2H, J=6.3 Hz), 4.31 (t, 2H, J=5.7 Hz), 7.42 (d,1H, J=8.4 Hz), 7.59 (m, 3H), 7.84 (d, 1H, J=8.1 Hz), 8.09 (s, 1H), 8.47(dd, 1H, J₁=2.4 Hz, J₂=8.7 Hz), 9.15 (s, 1H), 11.14 (s, 1H).

MS: m/z 572 (M+H)⁺.

General Procedures for the Preparation of Amide Substituted PyridylCompounds 42-45:

Compound B (50 mg) and the corresponding anhydride or acid chloride (>10eq) were placed in a pressure vessel and dissolved in dry pyridine(˜5-10 mls). For anhydride reactions, DMAP was added in catalyticamounts. The pressure vessel was flushed with nitrogen, sealed andstirred at 80° C. for 24-72 h. After cooling, the mixture wasconcentrated in vacuo and purified by gradient silica gel chromatographyor preparative HPLC.

42:N-(5-(1-cyclopropyl-2,3,6,7-tetrahydro-2,6-dioxo-3-propyl-1H-purin-8-yl)pyridin-2-yl)-N-(2-(pyridin-2-yl)ethyl)acetamide

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=12.80 min.

MS: m/z 474 (M+H)⁺.

43:N-[5-(1-Cyclopropyl-2,6-dioxo-3-propyl-2,3,6,7-tetrahydro-1H-purin-8-yl)-pyridin-2-yl]-N-phenethyl-benzamide

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=12.63 min.

¹H NMR (DMSO, d₆): 0.72 (m, 2H), 0.91 (t, 3H, J=7.5 Hz), 1.02 (m, 2H),1.70 (q, 2H, J=7.5 Hz), 2.61 (m, 1H), 2.97 (t, 2H, J=7.5 Hz), 3.96 (t,2H, J=6.3 Hz), 4.23 (t, 2H, J=7.2 Hz), 7.04 (d, 1H, J=8.4 Hz), 7.25 (m,4H), 7.49 (m, 2H), 7.62 (m, 1H), 7.95 (m, 2H), 8.18 (dd, 1H, J₁=2.7 Hz,J₂=8.7 Hz), 9.03 (d, 1H, J=1.8 Hz).

MS: m/z 535 (M+H)⁺.

44:N-(5-(1-cyclopropyl-2,3,6,7-tetrahydro-2,6-dioxo-3-propyl-1H-purin-8-yl)pyridin-2-yl)-N-(cyclopropylmethyl)benzamide

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=11.95 min.

¹H NMR (DMSO, d₆): 0.19 (m, 2H), 0.41 (m, 2H), 0.75 (m, 2H), 0.92 (t,3H, J=7.2 Hz), 1.05 (m, 2H), 1.67 (m, 1H), 1.75 (q, 2H, J=7.5 Hz), 2.65(m, 1H), 3.97 (m, 4H), 7.18 (d, 1H, J=8.4 Hz), 7.37 (m, 3H), 7.57 (m,2H), 7.99 (m, 1H), 8.26 (dd, 1H, J₁=2.7 Hz, J₂=8.7 Hz), 9.07 (d, 1H,J=1.8 Hz).

MS: m/z 485 (M+H)⁺.

45:N-(5-(1-cyclopropyl-2,3,6,7-tetrahydro-2,6-dioxo-3-propyl-1H-purin-8-yl)pyridin-2-yl)-N-(2-(pyridin-3-yl)ethyl)pivalamide

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=9.80 min.

MS: m/z 516 (M+H)⁺.

46:1,3-Dipropyl-8-[6-(N-[6-fluoronicotinoyl]methylamino)-3-pyridyl]xanthine

¹H NMR (DMSO, d₆): ¹H NMR (DMSO, d₆): 0.88 (m, 6H), 1.57 (m, 2H), 1.72(m, 2H), 3.50 (s, 3H), 3.86 (t, 2H, J=7.5 Hz), 4.00 (t, 2H, J=7.5 Hz),7.16 (dd, 1H, J₁=8.4 Hz, J₂=2.4 Hz), 7.45 (d, 1H, J=8.7 Hz), 7.92 (dt,1H, J₁=8.4 Hz, J₂=2.4 Hz), 8.19 (d, 1H, J=2.4 Hz), 8.36 (dd, 1H, J₁=8.7Hz, J₂=2.4 Hz), 8.99 (d, 1H, J=2.4 Hz).

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=10.01 min.

MS: m/z 466 (M+H)⁺.

47:3-Benzyl-1-(5-(2,3,6,7-tetrahydro-2,6-dioxo-1,3-dipropyl-1H-purin-8-yl)pyridin-2-yl)-1-(2-morpholinoethyl)urea

¹H NMR (DMSO, d₆): 0.77 (m, 2H), 0.95 (t, 3H, J=7.5 Hz), 1.08 (m, 2H),1.77 (m, 2H), 2.45 (m, 4H), 2.56 (m, 2H), 2.65 (m, 1H), 3.47 (m, 4H),4.03 (t, 2H, J=7.5 Hz), 4.15 (t, 2H, J=6.0 Hz), 4.46 (d, 2H, J=6.0 Hz),7.30-7.40 (m, 5H), 7.60 (d, 1H, J=9.0 Hz), 8.40 (dd, 1H, J₁=9.0 Hz,J₂=2.4 Hz), 9.02 (d, 1H, J=2.4 Hz), 9.45 (t, 1H, J=5.4 Hz).

HPLC condition: MeOH 20%-75% gradient in 10 minutes then MeOH 75%.Retention Time=10.33 min.

MS: m/z 573 (M+H)⁺.

48:3-Benzyl-1-(5-(1-cyclopropyl-2,3,6,7-tetrahydro-2,6-dioxo-3-propyl-1H-purin-8-yl)pyridin-2-yl)-1-(2-methoxyethyl)urea

¹H NMR (DMSO, d₆): 0.74 (m, 2H), 0.95 (t, 3H, J=7.5 Hz), 1.08 (m, 2H),1.77 (m, 2H), 2.67 (m, 1H), 3.30 (s, 3H), 3.59 (t, 2H, J=5.7 Hz), 4.03(t, 2H, J=7.5 Hz), 4.19 (t, 2H, J=5.7 Hz), 4.46 (t, 2H, J=5.7 Hz),7.26-7.40 (m, 5H), 7.58 (d, 1H, J=9.0 Hz), 8.41 (dd, 1H, J₁=9.0 Hz,J₂=2.4 Hz), 9.02 (d, 1H, J=2.4 Hz), 9.18 (t, 1H, J=5.7 Hz).

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=11.31 min.

MS: m/z 518 (M+H)⁺.

49:1-(5-(1-Cyclopropyl-2,3,6,7-tetrahydro-2,6-dioxo-3-propyl-1H-purin-8-yl)pyridin-2-yl)-1-(2-methoxyethyl)-3-(4-methoxyphenyl)urea

¹H NMR (DMSO, d₆): 0.77 (m, 2H), 0.96 (t, 3H, J=7.5 Hz), 1.08 (m, 2H),1.79 (m, 2H), 2.68 (m, 1H), 3.33 (s, 3H), 3.65 (t, 2H, J=5.7 Hz), 3.79(s, 3H), 4.04 (t, 2H, J=7.5 Hz), 4.24 (t, 2H, J=5.7 Hz), 6.94 (dd, 2H,J₁=6.9 Hz, J₂=2.1 Hz), 7.50 (dd, 2H, J₁=6.9 Hz, J₂=2.1 Hz), 7.57 (d, 1H,J=9.0 Hz), 8.44 (dd, 1H, J₁=9.0 Hz, J₂=2.4 Hz), 9.11 (d, 1H, J=2.4 Hz),10.90 (s, 1H).

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95%.Retention Time=11.47 min.

MS: m/z 534 (M+H)⁺.

50:1-Cyclopropyl-3-propyl-8-[6-(3-[3,4-difluorophenyl)-1-(2,3-dihydroxypropyl]ureido)-3-pyridyl]xanthine

To a solution of1-allyl-1-[5-(1-cyclopropyl-2,6-dioxo-3-propyl-2,3,6,7-tetrahydro-1H-purin-8-yl)-pyridin-2-yl]-3-(3,4-difluoro-phenyl)-urea(0.102 g, 0.1956 mmol) in acetone and water (15 mL) was added osmiumtetroxide (0.0780 mg, 0.3068 mmol) and 4-methylmorpholine-N-oxide (0.046mg, 0.3927 mmol). The reaction was stirred at 25° C. for 72 h at whichpoint heat was applied to 40° C. and the reaction was stirred foranother 48 h. The product was purified using a 43 g silica columnrunning a DCM/MeOH gradient from 0-8%. The fractions were concentrated,filtered, and washed with MeOH to afford a white solid.

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95% for 5minutes. Retention Time=11.98 min.

MS: m/z 556 (M+H)⁺.

51:1-Cyclopropyl-3-propyl-8-[6-(3-[trifluoro-m-tolyl)-1-(2,3-dihydroxypropyl]ureido)-3-pyridyl]xanthine

To a solution of1-allyl-1-[5-(1-cyclopropyl-2,6-dioxo-3-propyl-2,3,6,7-tetrahydro-1H-purin-8-yl)-pyridin-2-yl]-3-(3-trifluoromethyl-phenyl)-urea(0.098 g, 0.1770 mmol) in acetone and water (15 mL) was added osmiumtetroxide (0.055 g, 0.2163 mmol) and 4-methylmorpholine-N-oxide (0.036g, 0.3073 mmol). The reaction was stirred at 25° C. for 72 h at whichpoint heat was applied to 40° C., and the reaction was stirred foranother 48 h. The product was purified using a 43 g silica columnrunning a DCM/MeOH gradient from 0-8%. The fractions were concentrated,filtered, and washed with MeOH to afford a white solid.

HPLC condition: MeOH 40%-95% gradient in 10 minutes then MeOH 95% for 5minutes. Retention Time=13.23 min.

MS: m/z 588 (M+H)⁺.

Numerous modifications and variations of the present invention arepossible in light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims, the inventionmay be practiced otherwise that as specifically described herein.

1. A compound selected from the group:

or a pharmaceutically acceptable salt thereof.
 2. A pharmaceuticalcomposition comprising: (a) a therapeutically effective amount of acompound of claim 1; and (b) a pharmaceutically acceptable excipient. 3.A method for treating asthma comprising administering an effectiveamount of a compound claim 1 to a mammal in need of such treatment.
 4. Amethod for treating diabetic retinopathy, comprising administering aneffective amount of a compound claim 1 or a pharmaceutically acceptablesalt thereof to a mammal in need of such treatment.
 5. A compound ofclaim 1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 6. A compound of claim 1,wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 7. A compound of claim 1,wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 8. A compound of claim 1,wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 9. A con-mound of claim1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 10. A compound of claim1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 11. A compound of claim1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 12. A compound of claim1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 13. A compound of claim1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 14. A compound of claim1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 15. A compound of claim1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 16. A pharmaceuticalcomposition comprising: (a) a therapeutically effective amount of acompound of claim 5; and (b) a pharmaceutically acceptable excipient.17. A pharmaceutical composition comprising: (a) a therapeuticallyeffective amount of a compound of claim 6; and (b) a pharmaceuticallyacceptable excipient.
 18. A pharmaceutical composition comprising: (a) atherapeutically effective amount of a compound of claim 7; and (b) apharmaceutically acceptable excipient.
 19. A pharmaceutical compositioncomprising: (a) a therapeutically effective amount of a compound ofclaim 8; and (b) a pharmaceutically acceptable excipient.
 20. Apharmaceutical composition comprising: (a) a therapeutically effectiveamount of a compound of claim 9; and (b) a pharmaceutically acceptableexcipient.
 21. A pharmaceutical composition comprising: (a) atherapeutically effective amount of a compound of claim 10; and (b) apharmaceutically acceptable excipient.
 22. A pharmaceutical compositioncomprising: (a) a therapeutically effective amount of a compound ofclaim 11; and (b) a pharmaceutically acceptable excipient.
 23. Apharmaceutical composition comprising: (a) a therapeutically effectiveamount of a compound of claim 12; and (b) a pharmaceutically acceptableexcipient.
 24. A pharmaceutical composition comprising: (a) atherapeutically effective amount of a compound of claim 13; and (b) apharmaceutically acceptable excipient.
 25. A pharmaceutical compositioncomprising: (a) a therapeutically effective amount of a compound ofclaim 14; and (b) a pharmaceutically acceptable excipient.
 26. Apharmaceutical composition comprising: (a) a therapeutically effectiveamount of a compound of claim 15; and (b) a pharmaceutically acceptableexcipient.
 27. A method for treating asthma, comprising: administeringan effective amount of a compound claim 5 to a mammal in need of suchtreatment.
 28. A method for treating asthma, comprising: administeringan effective amount of a compound claim 6 to a mammal in need of suchtreatment.
 29. A method for treating asthma, comprising: administeringan effective amount of a compound claim 7 to a mammal in need of suchtreatment.
 30. A method for treating asthma, comprising: administeringan effective amount of a compound claim 8 to a mammal in need of suchtreatment.
 31. A method for treating asthma, comprising: administeringan effective amount of a compound claim 9 to a mammal in need of suchtreatment.
 32. A method for treating asthma, comprising: administeringan effective amount of a compound claim 10 to a mammal in need of suchtreatment.
 33. A method for treating asthma, comprising: administeringan effective amount of a compound claim 11 to a mammal in need of suchtreatment.
 34. A method for treating asthma, comprising: administeringan effective amount of a compound claim 12 to a mammal in need of suchtreatment.
 35. A method for treating asthma, comprising: administeringan effective amount of a compound claim 13 to a mammal in need of suchtreatment.
 36. A method for treating asthma, comprising: administeringan effective amount of a compound claim 14 to a mammal in need of suchtreatment.
 37. A method for treating asthma, comprising: administeringan effective amount of a compound claim 15 to a mammal in need of suchtreatment.
 38. A method for treating diabetic retinopathy, comprising:administering an effective amount of a compound claim 5 to a mammal inneed of such treatment.
 39. A method for treating diabetic retinopathy,comprising: administering an effective amount of a compound claim 6 to amammal in need of such treatment.
 40. A method for treating diabeticretinopathy, comprising: administering an effective amount of a compoundclaim 7 to a mammal in need of such treatment.
 41. A method for treatingdiabetic retinopathy, comprising: administering an effective amount of acompound claim 8 to a mammal in need of such treatment.
 42. A method fortreating diabetic retinopathy, comprising: administering an effectiveamount of a compound claim 9 to a mammal in need of such treatment. 43.A method for treating diabetic retinopathy, comprising: administering aneffective amount of a compound claim 10 to a mammal in need of suchtreatment.
 44. A method for treating diabetic retinopathy, comprising:administering an effective amount of a compound claim 11 to a mammal inneed of such treatment.
 45. A method for treating diabetic retinopathy,comprising: administering an effective amount of a compound claim 12 toa mammal in need of such treatment.
 46. A method for treating diabeticretinopathy, comprising: administering an effective amount of a compoundclaim 13 to a mammal in need of such treatment.
 47. A method fortreating diabetic retinopathy, comprising: administering an effectiveamount of a compound claim 14 to a mammal in need of such treatment. 48.A method for treating diabetic retinopathy, comprising: administering aneffective amount of a compound claim 15 to a mammal in need of suchtreatment.